Nitride semiconductor and semiconductor device

Abstract

According to one embodiment, a nitride semiconductor includes a nitride member. The nitride member includes a first nitride region, and a second nitride region. The first nitride region includes Alx1Ga1-x1N (0≤x1<1). The Alx1Ga1-x1N includes a first element. The first element includes at least one selected from the group consisting of Fe and Mn. The second nitride region includes Alx1Ga1-x1N (0≤x1<1). A direction from the first nitride region to the second nitride region is along a first direction. A second lattice length of the second nitride region in a first axis crossing the first direction is different from a first lattice length of the first nitride region in the first axis.

What is claimed is: 
     
         1 . A nitride semiconductor, comprising:
 a nitride member, the nitride member including:   a first nitride region including Al x1 Ga 1-x1 N (0≤x1<1), the Al x1 Ga 1-x1 N including a first element, the first element including at least one selected from the group consisting of Fe and Mn; and   a second nitride region including Al x1 Ga 1-x1 N (0≤x1<1), a direction from the first nitride region to the second nitride region being along a first direction,   a second lattice length of the second nitride region in a first axis crossing the first direction being different from a first lattice length of the first nitride region in the first axis.   
     
     
         2 . The nitride semiconductor according to  claim 1 , wherein
 a lattice length difference ratio of an absolute value of a difference between the second lattice length and the first lattice length to the first lattice length is 0.01% or more.   
     
     
         3 . The nitride semiconductor according to  claim 2 , wherein
 the lattice length difference ratio is 0.035% or more.   
     
     
         4 . The nitride semiconductor according to  claim 1 , wherein,
 the second lattice length is longer than the first lattice length.   
     
     
         5 . The nitride semiconductor according  claim 1 , wherein
 a first concentration of the first element in the first nitride region is higher than a second concentration of the first element in the second nitride region, or the second nitride region does not include the first element.   
     
     
         6 . The nitride semiconductor according to  claim 5 , wherein
 the second concentration is 1/10 or less of the first concentration.   
     
     
         7 . The nitride semiconductor according to  claim 1 , wherein
 a first concentration of the first element in the first nitride region is higher than an intermediate concentration of the first element at an intermediate position in the first direction of the second nitride region, or the intermediate position does not include the first element.   
     
     
         8 . The nitride semiconductor according to  claim 7 , wherein
 the intermediate concentration is 1/10 or less of the first concentration.   
     
     
         9 . The nitride semiconductor according to  claim 5 , wherein
 the first concentration is 1×10 17  cm −3  or more.   
     
     
         10 . The nitride semiconductor according to  claim 1 , wherein
 a first nitride region thickness of the first nitride region along the first direction is not less than 10 μm and not more than 1000 μm.   
     
     
         11 . The nitride semiconductor according to  claim 5 , wherein
 the nitride member further includes an intermediate region provided between the first nitride region and the second nitride region, and   the intermediate region includes crystal defects.   
     
     
         12 . The nitride semiconductor according to  claim 11 , wherein
 a thickness of the intermediate region along the first direction is not less than 10 nm and not more than 50 nm.   
     
     
         13 . The nitride semiconductor according to  claim 11 , wherein
 a density of dislocations in the second nitride region is higher than a density of dislocations in the first nitride region.   
     
     
         14 . The nitride semiconductor according to  claim 11 , wherein
 the intermediate region includes Al z1 Ga 1-z1 N (0≤z1<1).   
     
     
         15 . The nitride semiconductor according to  claim 14 , wherein
 a ratio of an absolute value of a difference between the z1 and the x1 to the x1 is 0.7 or less.   
     
     
         16 . The nitride semiconductor according to  claim 11 , wherein
 an intermediate concentration of the first element in the intermediate region decreases along a first orientation from the first nitride region to the second nitride region, and   a rate of a change of the intermediate concentration with respect to a change of a position along the first orientation is higher than a rate of a change of the first concentration with respect to the change of the position and higher than a rate of a change of the second concentration with respect to the change of the position.   
     
     
         17 . The nitride semiconductor according to  claim 1 , wherein
 the x1 is not less than 0 and not more than 0.1.   
     
     
         18 . A nitride semiconductor, comprising:
 a nitride member, the nitride member including:   a first nitride region including Al x1 Ga 1-x1 N (0≤x1<1), the Al x1 Ga 1-x1 N including a first element, the first element including at least one selected from the group consisting of Fe and Mn;   a second nitride region including Al x1 Ga 1-x1 N (0≤x1<1), a direction from the first nitride region to the second nitride region being along a first direction; and   an intermediate region provided between the first nitride region and the second nitride region, the intermediate region including Al z1 Ga 1-z1 N (0≤z1<1),   a first concentration of the first element in the first nitride region being higher than a second concentration of the first element in the second nitride region,   an intermediate concentration of the first element in the intermediate region decreasing along a first orientation from the first nitride region to the second nitride region, and   a rate of a change of the intermediate concentration with respect to a change of a position along the first orientation being higher than a rate of a change of the first concentration with respect to the change of the position and higher than a rate of a change of the second concentration with respect to the change of the position.   
     
     
         19 . The nitride semiconductor according to  claim 1 , wherein
 the nitride member further includes a third nitride region including Al x3 Ga 1-x3 N (0<x3≤1, x1<x3), and   the second nitride region is located between the first nitride region and the third nitride region.   
     
     
         20 . A semiconductor device, comprising:
 the nitride semiconductor according to  claim 19 ;   a first electrode;   a second electrode; and   a third electrode,   a direction from the first electrode to the second electrode being along a second direction crossing the first direction,   a position of the third electrode in the second direction being between a position of the first electrode in the second direction and a position of the second electrode in the second direction,   the second nitride region including a first partial region, a second partial region, and a third partial region,   a direction from the first partial region to the first electrode being along the first direction,   a direction from the second partial region to the second electrode being along the first direction,   the third partial region being located between the first partial region and the second partial region in the second direction, and a direction from the third partial region to the third electrode being along the first direction,   the first electrode being electrically connected to a portion of the third nitride region, and   the second electrode being electrically connected to another portion of the third nitride region.